1. Field of the Disclosure
This specification relates to a liquid crystal display device and a method of fabricating the same. More particularly, the specification relates to a liquid crystal display device having a color filter on TFT (COT) structure in which color filters, along with a thin film transistor, are formed on an array substrate, and a method of fabricating the same.
2. Background of the Disclosure
In general, a liquid crystal display device displays a desired image by individually providing data signals corresponding to image information to pixels arranged in a matrix form and controlling the light transmittance of the pixels.
Accordingly, the liquid crystal display device includes both a liquid crystal display panel where pixels are arranged in a matrix form and a driving unit for driving the pixels.
The liquid crystal display panel includes a thin film transistor array substrate and a color filter substrate which face each other and are attached such that they have a uniform cell gap therebetween and a liquid crystal layer in the cell gap.
A common electrode and a pixel electrode are formed on the liquid crystal display panel in which the array substrate and the color filter substrate are attached to each other in order to apply an electric field to the liquid crystal layer.
When a voltage of a data signal supplied to the pixel electrode is controlled such that a voltage is supplied to the common electrode, liquid crystal in the liquid crystal layer rotates due to a dielectric anisotropy according to the electric field formed between the common electrode and the pixel electrode. As a result, light is transmitted or blocked in each pixel thereby displaying a character or an image.
FIG. 1 is a view schematically showing a cross-section structure of a general liquid crystal device, which takes part of the cross-section structure of a data line area as an example.
Referring to FIG. 1, the general liquid crystal display device includes two glass substrates 5 and 10 and a liquid crystal layer (not shown) formed between the two glass substrates 5 and 10, with a cell gap maintained between them by a column spacer 40.
A gate line (not shown) and a data line 17 arranged in a matrix and defining pixel regions are formed on the lower glass substrate 10, and a thin film transistor, which is a switching element, is formed at the crossing of the gate line and the data line 17.
For an in-plane switching (IPS) mode, although not shown, a plurality of pixel electrodes and common electrodes for forming an electric field are alternately arranged within the pixel regions.
The thin film transistor includes a gate electrode connected to the gate line, a source electrode connected to the data line 17, and a drain electrode connected to a pixel electrode. Further, the thin film transistor includes a plurality of insulation films 15a, 15b, and 15c for insulation between these components and an active pattern that forms a conductive channel between the source electrode and the drain electrode by a gate voltage supplied to the gate electrode.
A color filter array is formed on the upper glass substrate 5, and the color filter array includes a black matrix 6, color filters 7, and an overcoat layer 9.
The general LCD device thus configured can bring about improvements in productivity and profitability as the size of a mother substrate for manufacturing a liquid crystal panel becomes larger, but has reduced the aperture ratio due to the increase in an attachment margin, that is, the width of the black matrix 6, in the manufacture of a liquid crystal panel. This lowers luminance and limits resolution, thus causing a decline in competitiveness.